 | This articleneeds additional citations forverification. Please helpimprove this article byadding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "TK85" – news ·newspapers ·books ·scholar ·JSTOR(January 2021) (Learn how and when to remove this message) |
 | |
| Developer | Microdigital Eletrônica |
|---|---|
| Manufacturer | Microdigital Eletrônica |
| Type | Home computer |
| Release date | 1983; 42 years ago (1983) |
| Operating system | 8K Sinclair BASIC |
| CPU | Z80 @ 3.25 MHz |
| Memory | 16 or 48 KB |
| Removable storage | External Compact Cassette recorder at 300 or 4200 bps |
| Display | Monochrome display on television; 24 lines × 32 characters or64 × 48 pixels graphics mode |
| Graphics | Discrete logic circuits |
| Power | 9V DC |
| Backward compatibility | ZX81 |
| Predecessor | TK83 |
| Successor | TK90X |
TheTK85 was aZX81 clone made byMicrodigital Eletrônica, a computer company located inBrazil.[1][2][3] It came with 16 or 48 KBRAM, and had aZX Spectrum–style case, similar to aTimex Sinclair 1500.[4][5]
Unlike the ZX81, the TK85 usedstandard logic components rather than a gate array ("ULA"), and during manufacture several of them were scraped so that competitors couldn't easily copy the circuit. The circuit board had space for aAY-3-8912 sound generator chip (compatible with theZonX-81 sound board), and although none came factory installed, it is possible to add the necessary circuits.[6]
The TK85 came with a copy of the 8KZX81 floating point BASIC, and an additional 2KEPROM, mapped to addresses 8192-10240, containing machine code routines for use with tape files. These routines could save withHISAVE, load withHILOAD and verify withHIVERIFY in "Hi-Speed" (4200 bps);[5] save and load, BASIC variables in 300 bps (standard ZX81 speed) usingSAVE andDLOAD functions and 4200 bps (Hi-Speed) usingDHSAVE andDHLOAD. These routines were all accessible usingRAND USR commands. The save to variable function could be used to make copies of programs on tape.[2]
The expansion port on the back of the computer is compatible with the ZX81, although some peripherals may not work due to conflicts with the 2K of extra ROM.
The rear of the computer featured a TV output (withoutvideo back porch), "EAR" and "MIC" sockets for connecting to an external tape recorder, a joystick port using aDIN socket (that simulated the5,6,7,8 and0 keys), a ZX81 compatible expansion port, space for a sound output socket, and a socket for the 9V external power supply.
Since the joystick used thecursor keys, and due to the circuitry for the keyboard, it wasn't possible to detect diagonal directions correctly.
 | ||
| Amstrad | ||
| Licenced systems | ||
| Timex Corporation | ||
| Cambridge Computer | ||
Lists ofclones | ||
Compatible or related systems |
| |
| Sinclair Research peripherals | ||
| Timex peripherals |
| |
| Other peripherals | ||
| People | ||
 | This computing article is astub. You can help Wikipedia byexpanding it. |
 | Thiscomputer hardware article is astub. You can help Wikipedia byexpanding it. |